Table 3.
| |||
---|---|---|---|
Entry | Substrate | Product | Yield (%) |
1 |
1c |
2c |
82 |
2 |
1d |
2d |
81 |
3 |
1e |
2e |
54 |
4 |
1f |
2f |
47 |
5 |
1g |
2g |
68b |
6 |
1h |
2h |
51b |
7 |
1i |
2i |
37 |
8 |
1j |
– | – |
9 |
1k |
2k |
36 |
10 |
1l |
2l |
88 |
11 |
1m |
2m |
58 |
Reactions were performed on 0.3–0.5 mmol scale in 3–5 mL solvent with 2 mol% 3a. A household 13 W light bulb was used as the light source. Reaction time ranged from 4 to 28 h.
Due to the instability of these hydrazine derivatives, the crude products were subjected to the cleavage reaction directly after Boc-deprotection. The yields given refer to overall yields for the two steps.